1. Field of the Invention
This invention relates to an electrosurgical unit and, more particularly, to an electrosurgical unit including a handpiece for surgical operations, with two switches for controlling at least two high frequency current outputs having waveforms different from each other.
2. Description of the Prior Art
There has heretofore been known an electrosurgical unit having a handpiece provided with two switches (hereinafter referred to as "one switch for cutting mode and the other switch for coagulation mode") for controlling at least two high frequency current outputs for the purpose of cutting and coagulation mode, which are different in waveform from each other. In this electrosurgical unit, the handpiece which is in the sterile field performs activation and interruption of the high frequency current outputs, while a main controller of the electrosurgical unit which is outside of the sterile field changes the operating conditions such as an output mode and a set value of the output.
Therefore, in the above-described electrosurgical unit, an operator, i.e. a surgeon performing a surgical operation by the use of the handpiece in the sterile field cannot change the output mode and the set value of the output directly as he desires and let his assistant perform the above changing operation instead of him, thus presenting such a problem that the controllability of the electrosurgical unit in the surgical operation is deteriorated.
To obviate this problem, there has been proposed an electrosurgical unit wherein two more switches for changing the operating conditions such as the output mode and the set value of the output are additionally provided on the handpiece as described in U.S. Pat. No. 4,632,109. With this improved electrosurgical unit, the surgeon performing the surgical operation in the sterile field by the use of the handpiece can directly change the output mode and the set value of the output.
This improved electrosurgical unit has had the above-described arrangement, whereby the handpiece provided with switches for transmitting a selective signal to change the operating conditions such as the output mode and the set value of the output and an additional circuit in the main controller for receiving the signal to select the operating condition in response to the selective instruction from the switches of the handpiece must be newly installed, so that there is no interchangeability with the conventional electrosurgical unit, thus presenting such a problem that the improved electrosurgical unit is uneconomical. Furthermore, due to the controllability and the installation space permitted in the handpiece, the number of the switches to be additionally provided is limited, whereby parts of the operating conditions which are changeable have been limited in number.